Elastic-fluid compressor.



C. G. CURTIS.

ELASTIG FLUID COMPRESSOR.

APPLICATION FILED 1116.4, 1896.

Patented Feb. 10, 1914.

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BLAsTw FLUID COMPRESSOR.

ILLIOATIN FILED AUGJI, 1896. u 1,086,755. Patented Feb. 10. 1914 3 SHEETS-SHEET 2.

WITNESSES z C. G. CURTIS.

ELASTIG FLUID COMPRESSOR.

APPLIo xTIoN FILED AUG.4, 189e.

Patented Feb. 10, 1914.

3 SHEETS-SHEET 3.

WITNESSES:

UNITED STATES PATENT OFFICE.

CHARLES G..CURTIS, 0F NEW YORK, N. Y., lASSIGNR. BY MESNE ASSIGNMENTS, '1'0` GENERAL ELECTRIC COMPANY, A CORPORATION 0F NEW YORK.

ELASTICJLUID COMPRESSOR.

To all whom 'it may concern Be it known that I, CHARLES Gr.I CURTIS, a citizen of the United States, residing at New York city, in the county and State of New York, have invented a certain new and useful Improvement in Elastic-Fluid` Compressors, of which the following is a specifi cation.

The object I have in view is to produce a method and apparatus for compressing air or other elastic fluid with a less expenditure of power and with a very much simpler and less costly form of apparatus than have heretofre been required. I have `found that, when velocity is imparted to air or other elastic fluid, the velocity may be converted into pressure by passing the fluid through a passagewith gradually converging or tapering walls; and that when such passage is properly proportioned, it will convertI the velocity wholly or largely into pressure without impeding the-flow ofthe fluid/beyond that resulting from friction on the walls of the passage. I have also found that a rotating wheel having a series of unsymmetrically curved buckets or Ivanes similar to thoser-f some forms of turbine, is a highly eflicient means for imparting velocit-yv to van elastic fluid. the fluid being drawn in on one side of the wheel and discharged'on the other side at a speed greater than that of the buckets.

The apparatus employed by me for carrying out my invention is in fact, a reversed elastic fluid turbine. having an expansion nozzle and provided with ,unsymmetrically curved buckets or vanes such as is described in applications for patent already filed by me (Serial No. 574.031, filed January 2, 1896 Patent No. 566,967. granted September l. 1896 and Serial No. 575,679, filed January 16. 1896 Patent No. 566,969, granted September 1, 1896.)

The turbine is revolved by a suitable power connection in the opposite direction to thatl in which it rotates as a means for developing mechanical power, the air or other elastic fluid being drawn into the exhaust opening cf the turbine and being eX- pelled through the expansion nozzle which now becomes a device for convert-ing velocity intopressure, instead of' oneffor converting pressure' into velocrty. I prefer t om;

Specification of Letters Patent.

'Patented Feb.1o,1914.

Application ined August 4, 1896, serial ivaoioe.

ploy two or more such fluid .compressors ronnected in series or succession. and having progressively slm-aller fluid passages, to accommodate the reduced volume of the fluid as its pressure is increased, and between the different compressorsI prefecto locate coolers for reducing the temperature of the fluid and lessening the power required to produce further compression. In this way the compressionvis produced by stages 'in two or more compressors. each comprising a wheel with unsymmetrcally curved buckets for imparting velocity to the fluid, and dis charging converging passages .for convert.- -ing thatvelocity into pressure. Each of these fluid compressors is contained in a separate fluid-tight shell so as to diminish the leakage at the clearances. The Wheels `of the several compressors are preferably located upon the same shaft, althoufg'h they may be located upon different'shal s. To further reduce the power required to effect the compression, the shells and passages may be water-jacketed. The rot-ating Wheels may have their curved buckets arranged so as to carry the fluid dfrom one side to the other of the wheel at its periphery, or these' buckets may be arranged so las to discharge outwardly or inwardly with reference to the periphery of the wheel. ACheck valves 'may be located between the different elements cf the compressor to prevent anyA iso In the accompanying drawings. forming a' part hereof,4 Figure 1 is a'view partly in elevation and partly in section. of -my elastic fluid compressor, composed of three elements. Fig. 2 is a view of the same apparatus illustrating ythe water-jacket upon the shells and passages: and.Fig. 3 is an end elevation and partial section showing a single compressor having its buckets arranged to proluce an, outward flow of the fluid.

' Referringparticular] to Figs. 1 and 2; B and C are rotating wheels mounted upon a shaft D,`having a. suitable power ccnnection. These wheels are provided on their periphery with complete circula-r ranges yof' curved vanes a.. which are held between they periphery of the Whe-el and .a ring or band Z1., 'which surrounds them.

cal in form, that is to say, their receiving ends c, are placed ata lesser or sharper angle than their discharging ends, d. The wheels, A, B andC are located'in separate shells or casings, E,F and G, which are packed about the shaft so as to be liuidtight. Entering these shells are inlet passages, H, I, K, and opposite these inlet passages, are converging discharging passages, I., M, N, set at the proper positions, the canes of the wheels occupying the space between these passages. The contractingpassageI and the shape and speed of the buckets and the angles of entrance and leaving must, of course, be adapted in each case to the work to be done: In other words, they must be such as would, if the machine were a turbine developing power,l convert the given pressure into velocity and then extract practically all the velocity and deliver the fluid lpractically in a state of rest at the discharge side of the buckets. 'If the conditions are properly fulfilled in this way, the. operation of the buckets in compressing, will be precisely the reverse of' what takes place in expanding-that is, the' buckets will take the air at the initial pressure in ,a state of rest and impart to it a high velocity, delivering it to the contracting or compressing passage-the column of air on the receiving side bein drawn in by the slight vacuum created t ere by the unsymmetrical shape of the buckets. In this way, the column of air is drawn into the buckets at a very low velocity, and in traversing the curved passages,its velocity is continually augmented until finally it is delivered from the other side of the buckets at a velocity which may be actually greater than that of the buckets themselves.

It is to be observed,l `that the column or jet of air enters the buckets only at a segmental portion where there is a free opening or passage, the walls of the case or shell in which the wheel revolves being set as closely as practicable to the 'edges of the buckets in order to prevent the drawing in of air at the other points of the circumference, and the loss by circulatiomfrom one side of the wheel to the other that would result therefrom.

Coolers O and P are located at the intermediate points between the element rrof the compressor, being connected by cheg valves Q, S and pipes R, T respectively, between the converging discharging passage L and inlet and between the converging discharging passage M and inlet K. The converging discharging passages L, M, N, discharge as shown into conduits of materially larger cross-section than the smaller ends or throats. of such assages. These conduits which extend t rough the coolers O, P, and pi es R, T, to the inlets B, C, and through t pipa U, to the final receiving chamber, act as reservoirs, and the rate of flow of the compressed air in them is little or nothing compared with the velocity of flowl through the converging discharging passages. As the column of air approaches the throats of the converging discharging passages its pressure continually increases and its velocity diminishes; but at these points it still has a very considerable velocity which is converted into pressure in entering the larger conduits in which the pressure is higher than in the throats of the discharging passages. The pressure in each case at the throat of the, converging discharging passage will be approximately.

fifty-three per cent. of the total rise in pressure` .in this stage of the operation, and the cross-section of the throat must be of the proper area to con'vey the given quantity of air at the pressure and velocity existing at this point. The pressure existing at any point of the passage-way will be the equiva lent in energy of the 'vis 'vi/va that has been consumed in developing such pressure less incidental losses by friction, etc. The elastic fluid under compression is finally discharged from the pipe U provided with check valve V. l

'Ihe shaft D being rotated by power in the direction shown by the arrows, air or other elastic fluid is drawn in at the inlet H by reason of the fact that the unsymmetrical form of the curved buckets of the wheel A causes those buckets to draw the airY inwardly at their ends c, which'have a sharp angle, with a greater effect than at their ends d, which have a fiat angle. y The fluid is discharged from the ends d of the buckets of the wheel A, with a velocity greater than that of the wheel, and enters the gradually tapering'or converging pas-l sage L, which converts the velocity into pressure.

'Ihe amount of convergence or ratio of contraction that takes place in the discharging passage will depend upon the velocity with which the fluid is delivered to that passage by the Wheel, lor in other Words the amount of velocity which it is desired to convert into pressure-the conditions here being exactly the reverse of those of an expansion apparatus or turbine as explained in the applicationsy filed by me hereinbefore referred to. In other words, this ratio of contraction, or the ratio betweenthe larger and smaller ends of 'the converging discharging passage will depend upon the respective pressures before and after compression at each stage of the operation. In any case, the convergence of the discharging passage will b'e such that its successive cross-sections will be diminished in area in the direction of the flow of the fluid to such a degree that the vis m'va or energy contained in the fluid in the form of velocity will be converted into a substantial equivalent. in the form of pressure by compression of the fluid in the converging passage.

The apparatus operates against the back pressure contained in the receiving chamber into which it discharges, and the pressure in that chamber is greater than that which exists in the fluid at the vanes of any one of the velocity-producing wheels.

From the passage L the fluid passes through the check valve Q, the cooler O, and pipe R. into the inlet I of the second Wheel B. where the operation is repeated, the discharging passage being made as much smaller than the similar part of the preceding wheel as the volume of the fluid jet is smaller by reason of its greater pressure. The converging or gradually tapering discharging )assage M converts the velocity produced fiy the wheel B into pressure. and thence the fluid passes through the check valve S. cooler l and pipe T into the inlet opening K of the third wheel C. from whence it is drawn through the buckets of the third wheel, being given an additional velocity which is converted into pressure by the gradually converging discharging passage N.

To further reduce the power required to compress the elastic fluid.y a water-jacket W (Fig. 2) may be employed. through which water-jacket a circulation of water may be maintained.

In Fig. 3 a single compressor element is shown` having its rotating buckets arranged to produce an outward flow of the fluid, X heilig the inlet opening, and Y the converging discharging passage. ln this construction the centrifugal force imparted to the fluid by the rotation of the wheel is also employed in producing the discharge of the fluid from the buckets and in increasing its velocity.

vhat I claim ist-- l. ln an elastic fluid compressor. the combination of-a velocity producing wheel. and means for converting the velocity into pressure. such means comprising a passage which receives the fluid from the wheel. and having tapered walls so as to produce a gradually diminishing cross sectional area` the amount of taper being such that the :21's m'rr/ of the fluid will be converted into a substantially equivalent pressure. and/,an enlarged passage connected with the posterior portion of the contracted passage. such enlarged passage being enlarged into a pressure chamber, in which the remaining velocity will be substantially converted into pressure.

2. ln an elastic fluid compressor. the combination of a velocity producing wheel and means for converting the Velocity into pressure. such means comprising a passage which receives the fluid from the wheel and havingta-pered walls so as to produce a gradually diminishing cross-sectional area, the amount of taper being such that the cis ifi/w of the fluid will be converted into a substantially equivalent pressure.

2i. In an elastic fluid compressor, the combination of a velocity producing wheel having unsymmetrical buckets. and means for converting the velocity into pressure. such means comprising a passage which receives the fluid from the wheel, and having tapered walls so as to produce a gradually diminishing cross sectional area. the amount of taper being such that the vis viva of the fluid will be converted into a substantially equivalent pressure. and an enlarged passage connected with the posterior portion of the contracted passage. such enlarged passage being enlarged into a pressure chamber. in which the remaining velocity will be substantially convert ed into pressure.

l. ln an elastic fiuid compressor, the combinaticn of a velocity producing wheel having unsynnnetrical buckets and means for converting the velocity into pressure, such means comprising a passage which receives the fluid from the wheel, and having tapered walls so as to produce a gradually diminish ing cross-sectional area. the amount of taper being such that the Ms rfi/a of the fluid will be converted into substantially equivalent pressure.

5. The combination with a velocity-producing wheel. discharging fluid at a for ward angle. of a pressure producing passage having contracting walls receiving the fluid from the wheel and set at a forward angle corresponding with the angle of discharge of tbe fluid from the wheel. substantially as set forth.

(i. ln an elastic fluid compressor. the combination of' a velocity producing wheel. the wheel discharging at a forward angle. and means for converting the velocity into pressure. such means comprisingr a passage which receives the fiuid from the wheel. the passage being set at a forward angle corresponding with the angle of discharge of the fiuid from the wheel. and having tapered walls so as to produce a gradually diminishing cross sectional area. the amount of taper being such that the mls viva of the fluid will be converted into a substantially equivalent pressure. and an enlarged passage connected with the posterior portion of the contracted passage` such enlarged passage being enlarged into a pressure chamber. in which the remaining velocity will be substantially converted into pressure.

T. ln an elastic flui'd compressor. the combination of a velocity producing wheel, the wheel discharging at a forward angle. and means for converting the velocity into pressure, such means comprising a passage which receives the fluid from the wheel, the

passage being Iset atv a forward angle corresponding with the angle of discharge of the i'luid from the wheel. such passage being enlarged into a pressuie chamber, in Which the velocity will be substantially converted into pressure.

8. lu an elastic fluid compressor, the c0m bination ot' a vi'elocity producing wheel having' unsynunetrical buckets, the wheel dischargingl at a forward angle. and means for converting the velocity into pressure, such means comprising a passage which receives the fluid rfrom the wheel. the passage being set at a forward angle corresponding With the angle of discharge of the Huid from the wheel. and havin'.r tapered walls .so as to produce a gradually diminishing cross sectional area. the amount of taper being such that the fois cina of the Huid will be converted into a substantially equivalent pressure. and an enlarged passage connected with the posterior portion of the contracted passage. such enlarged passage being enlarged into a pressure chamber. in which the remaining velocity will be substantially converted. into pressure.

El. ln an elastic fluid Compressor, the combination of a velocity producing wheel, havingl unsymmetrical buckets. the wheel discharging at a for 'ard angle. and means for converting the velocity into pressure, such lneaiis comprising a passage which receives the fluid from the wheel. the passage being set at a forward angle corresponding with the angle of discharge of the fluid from the wleel. such passage being enlarged into a pressure chamber. in which the velocity will be .substantially converted into pressure.

l0. ln an elastic fluid Compressor, the combination of two or more velocity producing wheels and converging pressure producing pass-ages located in series or succession. the said passages being of successively7 diminished cross-section to carry the fiuid at decreased volume and increased densities. ll. ln an elastic Huid compressor, the combination of two or more velocity producing wheels. such wheels` being connected together in series or succession. and means between the wheels for converting the velocity into pressure. such melius comprising passages which receive the fluid from the wheels. the passagesI beingr of successively diminished cross section to carry the fluid at decreased volume and increased densities each of such passages havingr tapered walls so as to produce a gradually diminishing cross sectional area. the amount of taper beingI such that the ma m'wl of the fluid will he converted into a substantially equivalent pressure. and an enlarged passage connected with the posterior portion of the contracted passage. such enlarged passage being en lai-ged into a pressure chamber, in which the remaining velocity will be substantially coni erted into pressure.

l2. ln an elastic fluid compressor, the combination of two or more velocity producing wheels, such Wheels being connected together in series or succes-sion, and means between the wheels for converting the velocity into pressure such means comprising passages which receive the fiuid from the wheels. the passages being of successively diminished cross section to carry the fluid at decreased volume and increased densities, each ot' such passages being enlarged into a pressure chamber in which the velocity will l e substantially converted into pressure.

tl. ln an elastic fiuid compressor, the 80 combination of two or more velocity producing wheels and converging pressure producing passages located in series or succes` sion the said passages being of successively diminished cross-section to carry the fluid at 8E decreased volume and increased. densities, with one or more coolers connected between the two or more eleiiients-of the compressor.

ll. ln an elastic fluid compressor, the

combination of two or nioi'e velocity produc- 90 passages which receive the fluid from the wheels, the passages heilig of successively diminished cross section to carry the fluid at decreased volume and increased densities. each of such passages having tapered walls .so as to produce a gradually diminishing cross sectional area the amount of taper lieing such that the e/'srim. of the fluid will be converted into a substantially equivalentI pressure, and an enlarged passage connected.

with the posterior portion of the contracted passage, such enlarged passage being enlarged into a pressure chamber. in which tht` remaining velocity will be substantially converted into pressure, and with coolers between the two or more elements of the compressor.

15. In an elastic fluid compressor. the eon'iliination ot' two or more velocity producing wheels. such wheels heilig connected together 1n series or succession, and means be- 11a tween the wheels fer converting the velocity into pressure. such means comprising passages which receive tlie fluid from the wheels, the passages being of successively diminished crc-ss section to carry the fluid at decreased volume and increased densities. each of such passages being enlarged into a pressure chamber in which the velocity will be substantially converted into pressure, and

with coolers between the two or more elements of the compressor.

tt'. in an elastic fluid compressor. the ccmhinatieii of two or more velocity producing wheels, such wheels being connected together in series or succession, and means between the wheels for converting the velocity into pressure, such means comprising passages which receive the fluid from the wheels. the passages being of successively diminished cross section to carry the fluid at decreased volume and increased densities, each of such passages having tapered walls so as to produce a gradually diminishing cross sectional area. the amount of -taper being such that the fais rim of the fluid will be converted into a substantially equivalent pressure. and an enlarged passage connected with the posterior portion of the contracted passage. such enlarged passage being enlarged into a pressure chamber, in which the remaining velocity will be substantially converted into pressure, and check valves for preventing backward flow of the fluid.

17. In an elastic fluid colnpressor. the combination of two or more velocity producing wheels, such wheels being connected together in series or succession` and means between the wheels for converting the velocity into pressure, such means comprising passages which receive the fluid from the wheels, the passages being of successively diminished cross section to carry the fluid at decreased volume and increased densities, each of such passages being enlarged into a pressure chamber. in which the velocity will be substantially converted into pressure. and check valves for preventing backward flow of the fluid.

18. The combination with two or more velocity producing wheels and converging pressure-producing passages. located in series or succession. with one or more coolers connected between the two or more elements of the compressor. and check valves lor preventing the backward flow of the fluid.

19. In an elastic fluid compressor. the combination of two or more velocity producing Wheels, such wheels being connected together in series or succession, and means between the wheels for converting the velocity into pressure, such means comprising passages which receive the fluid from the wheels. the passages beingr of successively diminished cross section to carry the fluid at decreased volume a'ud increased densities` each of such passages having tapered walls so as to produce a gradually diminishing cross sectional area the amount of taper being such that the cis vica of the fluid will be converted into a substantially equivalent pressure. and an enlarged passage connected wit-h the posterior portion of the contracted passage. such enlarged passage being enlarged into a pressure chamber. in which the remaining velocity will be substantially converted into pressure. and with coolers between the two or more elements of the compressor, and check valves for preventing backward flow of the uid.

20. In an elastic fluid compressor, the combination of two or more velocity producing wheels, such wheels being connected together in series or succession, and means be tween the wheels for converting the velocity into pressure, suc means comprising passages which receive the fluid from the Wheels, the passages being of successively diminished cross section to carry the fluid at decreased volume and increased densities. each of such passages being enlarged into a pressure chamber in which the velocity will be substantially converted into pressure, and with coolers between the two or more elements of the compressor, and check valves for preventing backward flow of the fluid.

21. In an elastic fluid compressor, the combination of two or more velocity producing wheels and two or more separate fluidtightl shells, in which such wheels are located, such wheels and shells being connected together in series or succession, with converging passages receiving the discharge from such wheels and converting velocity into pressure, each said passage enlarging upon a curved line, the enlargement being such that the velocity will be substantially converted into pressure. substantially as set forth.

22. In an elastic fluid compressor, the combination of two or more velocity producing wheels, such wheels being connected together in series or succession, two or more separate fluid tight shells in which said wheels are located, and means between the wheels for converting the velocity into pressure, such means comprising passages which receive the fluid from the wheels, the passages being of successively diminished cross section to carry the fluid at decreased volume and increased densities. each of such passages having tapered walls so as to produce a gradually diminishing cross sectional area, the amount of taper being such that the fm's cica of the Huid will be converted into a substantially equivalent. pressure. and an enlarged passage connected with the posterior portion of the contracted passage` such enlarged passage being enlarged into a pressure chamber. in which the remaining velocity will be substantially converted into pressure.

23. In an elastic fluid compressor. the combination of two or more velocity produc ing wheels, such wheels being connected together in series or succession, two yor more separate fluid tight shells in which said wheels are located. and means between the wheels for converting the velocity into pressure, such means comprising passages which receive the fluid from the wheels, the passages being of successively diminished cross lll section to carry the fluid at decreased volume and increased densities, each of such passages being enlarged into a pressure chamber, in which the velocity will be substantially converted into pressure.

24. In an elastic fiuid compressor, the combination with two or more velocity producing wheels located in separate fluid-` tight shells, and two or lnore converging;` discharging passages converting velocityi into pressure, each said passage enlarging upon a curved line, the enlargement being such that the velocity will be substantially converted into pressure. of' a water-jacket surrounding the shells and passages. substantially as set forth.

Q5. ln an elastic fluid compressor, the combination of two or more velocity producing wheels, such wheels being connected together in series or succession, two or more separate fluid tight shells in which said wheels are located. and means between the wheels for converting the velocity into pressure. such means comprising passages which receive the fluid from the wheels. the passages being of successively diminished cross section to carry the fluid at decreased volume and increased densities. each ot' such passages having tapered walls so as to produce a gradually diminishing cross sectional area. the amount of taper being such that the cfs mica of the fluid will be converted into a substantially equivalent pressure. and an enlarged passage connected with the posterior portion of the contracted passage, such enlarged passage being enlarged into a pressure chamber, in which the remaining velocity will be substantially" converted into pressure.r and a water jacket surrounding the shells and passages.

QG. ln an elastic fluid compressor, the combination of` two or more velocity producing wheels. such wheels being connected together in series or succession, two or more separate fluid tight shells in which said wheels are located. and means between the wheels t'cr converting the velocity into pressure. such means comprising passages which receive the fluid from the wheels. the passages being of' successively diminished cross section to carry the fluid at decreased volume and increased densities, each of such passages being enlarged into a pressure chamber. in which the velocity will be substantially converted into pressure, and a water jacket surrounding the shells and passages.

27. The combination with two or more velocity producing wheels connected in succession. of means for converting velocity into pressure following each wheel consisting of a passage which receives the fluid from the wheel, such passage being gradually enlarged into a pressure chamber in which the pressure produced is maintained,

and a passage connecting each pressure producing means except after the last wheel with the inlet of the next succeedin velocity producing wheel which conveys t e fiuid l without material reduction in its pressure,

substantially as set forth.

'28. An elastic iiuid compressor, having a velocity producing wheel which discharges into a means for converting velocity into pressure, the said means consisting of a reversed expansion nozzle.

29. An elastic fluid compressor having a velocity producing wheel which discharges into a means for converting velocity into pressure. the said means consisting of a pas sage with converging and diverging walls. the amount oi convergence being such that 'the pressure at the throat of the passage is approximately 53 per cent (for air) of the total rise in pressure by the traverse of the fluid through tie passage. the cross-section et' the throat being otl the pro-per area to convey a given quantity of' fluid at the pressure and velocity existing at this point.

rt). ln an elastic fluid compressor. the cowbination with a rotary impeller with outwe rd flow. having curved radiating buckets which produce velocity by centrifugal action as well as by the configuration of the buckets. of a means for converting velocit)v into pressure into which said impeller discharges. the said means consisting of a re versed expansion nozzle.

2l. ln an elastic fluid compressor. the combination with a rotary impeller with outward flow. having unsynnnetrical curved buckets. the receiving ends ot' which are placed at a sharper angle than their discharge ends. which produce velocity by centrifugal action as well as by the configuration of the buckets. of a means for converting velocity into pressure. into which said impeller discharges. the said means consisting of' a reversed expansion nozzle.

ln an elastic fluid compressor. the combination with a rotary impeller with outward flow. having curved buckets which discharge at a forward angle. thereby producing velocity by centrifugal action. of a means for converting velocity into pressure. into which said impeller discharges. the said means consisting of a reversed expansion nozzle.

33. ln an elastic fluid compressor. the combination with a rotary inipeller with outward flow. having curved radiating buckets which produce velocity by centrifugal action as well as by the configuration of the buckets. of a nozzle adapted to receive fluid from the impeller which has inclined walls, producing a change of area in the direction of flow and has such position and dimensions that it will guide the fluid in its passage from the impeller in substantially the direction of the movement imparted to it by the impeller, the rate of change of "area being so proportioned to the movement and elasticity of the fluid that a considerable portion or all of the velocity of the fluid will be converted into pressure during its passage'through the nozzle.

3l. In an elastic fluid compressor, the combination with a rotary impeller with outward flow, and having unsymmetrical curved buckets, the receiving ends of which are placed at a sharper angle than their discharge ends, which produce velocity by centrifugal action as well as by the configura` tion of the. buckets. of a nozzle ada ted to receive fluid from the impeller whlch has inclined walls, producing a change of area in the direction of flow and has such position and dimensions that it will guide the fluid in its passage from the impeller in substantially the direction of the movement impart- 'ed to it by the impeller. the rate of change of area being so proportioned to the move` lnent and elasticity of the fluid that a considerable portion or all of the velocity of the fluid will be converted into pressure during its passage through the nozzle.

35. In an elastic fluid compressor', the colnbination with a rotary impeller with outward flow and having curved buckets 'which discharge at a forward angle, thereby producing velocity by centrifugal action, of a nozzle adapted to receive fluid from the impeller which has inclined walls, producing a change of area in the direction of flow and has such position and dimensions that it will guide the fluid in its passage from the impeller in substantially the direction of the movement imparted to ity by` the impeller, the rate of change or area being so proportioned to the movement and elasticity of the Huid that a considerable portion of all of the velocity of the fluid will be converted into Ipressure during its passage through the nozz e.

36. In an elastic fluid compressor, the combination with a rotary impeller with outward flow, of a means for converting velocity into pressure, into which said impeller discharges, the said means consisting of a reversed expansion nozzle.

37. In an elastic fluid compressor, the combination with a rotary impeller with outward flow, of a nozzle ada ted to receive fluid from the impeller Whic has inclined walls, producing a change of area in the direction of flow and has such position and dimensions that it will uide the fluid in its passage from the impe ler in substantially the direction of the movement imparted to it by the impeller, the rate of change of area. bein so proportioned to the movement and elasticity of the fluid that a considerable portion or all of the velocity of the fluid will be converted into pressure during its passage through the nozzle.

38. In an elastic fluid compressor, the combination with a velocity producing wheel, of a nozzle adapted to receive fluid from the wheel which has inclined walls, producing a change of area in the direction of flow and has such position and dimensions that it will guide the fluid in its pasv sage from the wheel in substantially the direction of' the movement imparted to it by the wheel, the rate of change of area being so proportioned to the movement and elasticity of the fluid that a considerable ortion or all of the velocity of the fluid wi l be converted into pressure during its passage through the nozzle.

39. In an elastic fluid compressor, the combination with means for producing velocity. of a means for converting velocity into pressure into which said velocity producing means discharges, the said velocity converting means consisting of a reversed expansion nozzle.

40. In an elastic fluid compressor, the combination with means for producing velocity. of a nozzle adapted to receive fluid from the velocity producing means, which has inclined walls, producing a change of area in the direction of flow and has such position and dimensions that it will guide the fluid in its passage from the velocityA CHARLES G. CURTIS.

Witnesses:

EUGENE CoNRAN, JNO. R. TAYLOR.

Copies of thu patent may be obtained for nve cents each, by addressing the Commissioner of Patents. Washington, D. 0. 

